Medical skin mountable device

ABSTRACT

A medical device is provided comprising a transcutaneous device unit and a reservoir unit. The transcutaneous device unit comprises a transcutaneous device for transporting a fluid through a skin portion of a subject, and a mounting surface adapted for application to the skin of the subject. The reservoir unit comprises a reservoir adapted to contain a fluid drug, the reservoir comprising an outlet means allowing the transcutaneous device to be arranged in fluid communication with an interior of the reservoir, and an expelling assembly for expelling a fluid drug out of the reservoir and through the skin of the subject via the transcutaneous device. The transcutaneous device unit and the reservoir unit further comprise coupling means allowing the reservoir unit to be secured to the transcutaneous device unit in the situation of use. By this arrangement a two-unit system is provided which can be used in a convenient and cost-effective manner.

CROSS REFERENCE TO RELATED APPLICATIONS

This Application is a continuation of International Application serialno. PCT/DK2004/000726 filed Oct. 21, 2004 and claims priority fromEuropean Application serial no. EP 03024626.8 filed Oct. 27, 2003 and toU.S. Provisional Application Ser. No. 60/518,836 filed Nov. 10, 2003.

FIELD OF THE INVENTION

The present invention generally relates to devices which are adapted forapplication to a skin surface of a subject and comprise a transcutaneousdevice for introduction of a fluid through the skin of the subject. Inspecific aspects, such devices may comprise a reservoir adapted tocontain a fluid drug, and expelling means for expelling fluid drug outof the reservoir and through the skin of the subject via thetranscutaneous device.

BACKGROUND OF THE INVENTION

In the disclosure of the present invention reference is mostly made tothe treatment of diabetes by injection or infusion of insulin, however,this is only an exemplary use of the present invention.

Portable drug delivery devices for delivering a drug to a patient arewell known and generally comprise a reservoir adapted to contain aliquid drug and having an outlet in fluid communication with a hollowinfusion needle, as well as expelling means for expelling a drug out ofthe reservoir and through the skin of the subject via the hollow needle.Such devices are often termed infusion pumps.

Basically, infusion pumps can be divided into two classes. The firstclass comprises infusion pumps which are relatively expensive pumpsintended for 3-4 years use, for which reason the initial cost for such apump often is a barrier to this type of therapy. Although more complexthan traditional syringes and pens, the pump offer the advantages ofcontinuous infusion of insulin, precision in dosing and optionallyprogrammable delivery profiles and user actuated bolus infusions inconnections with meals.

Addressing the above problem, several attempts have been made to providea second class of drug infusion devices that are low in cost andconvenient to use. Some of these devices are intended to be partially orentirely disposable and may provide many of the advantages associatedwith an infusion pump without the attendant cost and inconveniencies,e.g. the pump may be prefilled thus avoiding the need for filling orrefilling a drug reservoir. Examples of this type of infusion devicesare known from U.S. Pat. Nos. 4,340,048 and 4,552,561 (based on osmoticpumps), U.S. Pat. No. 5,858,001 (based on a piston pump), U.S. Pat. No.6,280,148 (based on a membrane pump), U.S. Pat. No. 5,957,895 (based ona flow restrictor pump (also know as a bleeding hole pump)), U.S. Pat.No. 5,527,288 (based on a gas generating pump), or U.S. Pat. No.5,814,020 (based on a swellable gel) which all in the last decades havebeen proposed for use in inexpensive, primarily disposable drug infusiondevices, the cited documents being incorporated by reference. U.S. Pat.No. 6,364,865 discloses a manually held infusion device allowing twovial-type containers to be connected and a pressure to be build up inone of the containers to thereby expel a drug contained in thatcontainer.

The disposable pumps generally comprises a skin-contacting mountingsurface adapted for application to the skin of a subject by adhesivemeans, and with the infusion needle arranged such that in a situation ofuse it projects from the mounting surface to thereby penetrate the skinof the subject, whereby the place where the needle penetrates the skinis covered while the appliance is in use. The infusion needle may bearranged to permanently project from the mounting surface such that theneedle is inserted simultaneously with the application of the infusionpump, this as disclosed in U.S. Pat. Nos. 2,605,765, 4,340,048 and in EP1,177,802, or the needle may be supplied with the device in a retractedstate, i.e. with the distal pointed end of the needle “hidden” insidethe pump device, this allowing the user to place the pump device on theskin without the possibility of observing the needle, this as disclosedin U.S. Pat. Nos. 5,858,001 and 5,814,020. In addition to pumps,alternative means for transporting a fluid drug may be used, e.g.iontophoresis as discussed below.

Although it can be expected that the above described second class offully or partly disposable infusion devices can be manufacturedconsiderably cheaper than the traditional durable infusion pump, theyare still believed to be too expensive to be used as a real alternativeto traditional infusion pumps for use on an every-day basis.

Before turning to the disclosure of the present invention, a differenttype of device relying on the insertion of a needle or needle-likestructure will be described.

Although drug infusion pumps, either disposable or durable, may provideconvenience of use and improved treatment control, it has long been anobject to provide a drug infusion system for the treatment of e.g.diabetes which would rely on closed loop control, i.e. being more orless fully automatic, such a system being based on the measurement of avalue indicative of the condition treated, e.g. the blood glucose levelin case of insulin treatment of diabetes.

A given monitor system for measuring the concentration of a givensubstance may be based on invasive or non-invasive measuring principles.An example of the latter would be a non-invasive glucose monitorarranged on the skin surface of a patient and using near-IRspectroscopy, however, the present invention is concerned primarily withdevices comprising a transcutaneous device such as a needle-formedsensor element.

The sensor may be placed subcutaneously being connected to externalequipment by wiring or the substance (e.g. fluid) to be analysed may betransported to an external sensor element, both arrangements requiringthe placement of a subcutaneous component (e.g. small catheter ortubing), the present invention addressing both arrangements. However,for simplicity the term “sensor” is used in the following for both typesof elements introduced into the subject.

DISCLOSURE OF THE INVENTION

Having regard to the above-identified problems, it is an object of thepresent invention to provide a skin mountable drug delivery device orsystem and components therefore, which allow such a device or system tobe used in a convenient and cost-effective manner. The configuration ofthe system and the components therefore should contribute in providing amedical delivery means which allows for easy and swift operation yetbeing reliable in use.

In the disclosure of the present invention, embodiments and aspects willbe described which will address one or more of the above objects orwhich will address objects apparent from the below disclosure as well asfrom the description of exemplary embodiments.

Thus, corresponding to a first aspect, a medical device comprising atranscutaneous unit and a reservoir unit is provided, wherein thetranscutaneous unit comprises transcutaneous means for transporting afluid through a skin portion of a subject, and a mounting surfaceadapted for application to the skin of the subject. The reservoir unitcomprises a reservoir adapted to contain a fluid drug, the reservoircomprising an outlet allowing the transcutaneous means to be arranged influid communication with an interior of the reservoir, and expellingmeans for, in a situation of use, expelling a fluid drug out of thereservoir and through the skin of the subject via the transcutaneousmeans. The transcutaneous unit and the reservoir unit further comprisecoupling means allowing the reservoir unit to be secured to thetranscutaneous unit in the situation of use.

The term “transcutaneous” covers all forms of administration in which afluid is transported through a portion of the skin, e.g. intradermal orsubcutaneous administration. The transcutaneous means may be in the formof a transcutaneous device, a jet injection means or electrodes allowingan ionic agent to permeate from a predetermined site on the surface ofskin into the subcutaneous tissue of the subject by using the principleof iontophoresis. For a more thorough discussion of iontophoresisreference is made to U.S. Pat. No. 6,622,037 hereby incorporated byreference. Depending on the nature of the transcutaneous means theexpelling means may be of different configuration and nature. Forexample, when one or more hollow infusion needles or cannulas are used,the expelling means may be arranged to force or suck the fluid drug fromthe reservoir, whereas in the case of iontophoresis the expelling meanswould be means for applying a current over a set of electrodes, i.e.“driving” means.

Corresponding to a further aspect, a medical device comprising atranscutaneous device unit and a reservoir unit is provided, wherein thetranscutaneous device unit comprises a transcutaneous device, and amounting surface for application to the skin of the subject. Thereservoir unit comprises a reservoir adapted to contain a fluid drug,and an expelling assembly adapted for cooperation with the reservoir toexpel the fluid drug out of the reservoir and through the skin of thesubject via the transcutaneous device. The transcutaneous device unitand the reservoir unit are further adapted to be secured to each otherin a situation of use thereby allowing a fluid communication to beestablished between the reservoir and the transcutaneous device. Thetranscutaneous device unit and the reservoir unit may comprisereleasable coupling means allowing the reservoir unit to be secured tothe transcutaneous device unit in a situation of us. Such a medicaldevice comprising two units may also be considered a medical system. Thetranscutaneous device unit and the reservoir unit may each comprise ahousing within which the transcutaneous device respectively thereservoir and the expelling assembly are arranged.

The term expelling assembly covers an aggregation of components orstructures which in combination provides that a fluid can be expelledfrom the reservoir. The expelling assembly may e.g. be a mechanical pump(e.g. a membrane pump, a piston pump or a roller pump) in combinationwith electronically controlled actuation means, a mechanically drivenpump (e.g. driven by a spring), a gas driven pump or a pump driven by anosmotic engine. The expelling assembly may also me in the form of anaggregation of components or structures which in combination providesthat a fluid can be expelled from the reservoir when the expellingassembly is controlled or actuated by a controller external to theexpelling assembly.

The transcutaneous device (which term also covers the similar termstranscutaneous access device and transcutaneous access tooltraditionally used in this technical field) may be in the form of apointed hollow infusion needle, a micro needle array, or a combinationof a relatively flexible per se blunt cannula with a pointed insertionneedle may provide a pointed transcutaneous device, the insertion needlebeing retractable after insertion of the blunt portion of thetranscutaneous device. In the latter case the portion of thetranscutaneous device actually placed in the subject and subsequentlyretracted by the herein described retraction means does not necessarilycomprise a pointed end allowing the combined transcutaneous device to beinserted through the skin, such a pointed end being withdrawn duringinsertion of the transcutaneous device. The cannula is advantageouslysoft and flexible relative to the insertion needle which typically is asolid steel needle. In the disclosure of the present invention as wellas in the description of the exemplary embodiments, reference willmostly be made to a transcutaneous device in the form of an infusionneedle. The length of the transcutaneous device may be chosen inaccordance with the actual application, e.g. a hollow steel needle whichmay be inserted at a substantially right angle relative to the skinsurface may have an inserted length of 2-8 mm, preferably 3-5 mm,whereas a cannula which may also be inserted at an oblique anglerelative to the skin surface may be somewhat longer, e.g. 4-20 mm.

The mounting surface is adapted for application against the skin of asubject (e.g. user or patient) and may be held in contact with the skinby attaching means external to the mounting surface (e.g. coupling meansallowing the medical device to be coupled to a skin mountable device, oran adhesive bandage or a dressing) or by adhesive means provided on themounting surface. The mounting surface may also be adapted for mountingtowards the skin via an interposed component of a skin mountable device,e.g. a skin mountable device may comprise a receiving portion to whichthe medical device is attached, the transcutaneous device being insertedinto the skin through an aperture in the receiving portion.

By the above arrangement different concepts can be realized. Forexample, by providing at least two different of one of the units, itwill be possible to provided two or more combinations, wherein eachcombination of a transcutaneous device unit and a reservoir unitprovides an assembly will have different capabilities as discussed infurther detail below. In case the units are provided with releasablecoupling means, one of the units can be exchanged with a new ordifferent unit yet allowing the other unit to be re-used, therebylengthening the operational life of the re-used unit. Thus, the presentinvention provides in an exemplary embodiment a device in which thecomponents providing the interface with the user is incorporated in afirst unit whereas the components providing the drug delivery per se isincorporated in a second unit, this allowing the combined components tobe combined or exchanged in a simple, reliable and user-friendly way.

For example, the reservoir unit may be provided with an amount of drugand a delivery pump comprising an energy source allowing the drug to bedelivered over e.g. 10 days, whereas the transcutaneous device unit maybe provided with a transcutaneous device and an adhesive surface on themounting surface having an expected (or recommended) operational life of2 days, this allowing the reservoir unit to be used with 5transcutaneous device units over a period of 10 days, this considerablylowering the total costs of using the combined device. The reservoir maybe pre-filled or adapted to be filled one or more times.

On the other hand, a transcutaneous device unit may be provided withe.g. a needle or a soft cannula, and adhesive means (e.g. of the typeused for attaching colostomy bags) allowing the needle unit to bemounted and used over an extended period of time, the reservoir unithaving a shorter expected operational life, e.g. when relatively largeamounts of drugs have to be infused. Alternatively, different reservoirunits with different types of drugs may be used in combination with sucha “long-term” mounted needle unit.

For ease of use, the fluid communication between the needle and thereservoir may be established when the needle unit and the reservoir unitare secured to each other, just as the expelling means may be activatedwhen the needle unit and the reservoir unit are secured to each otherand de-activated when the units are released from each other. Indeed,one or both of the operations may also be performed manually by theuser.

In an exemplary embodiment the expelling assembly comprises a pumphaving an inlet adapted to be arranged in fluid communication with theoutlet of the reservoir, and an outlet adapted to be arranged in fluidcommunication with the transcutaneous device, thereby allowing thetranscutaneous device to be arranged in fluid communication with theinterior of the reservoir. By such an arrangement the pump will serve asa suction pump drawing drug from the reservoir which consequently willhave to be either collapsible or vented in case a non-collapsiblereservoir is used. The expelling assembly may also be in the form of anarrangement adapted to pressurize the reservoir, e.g. an arrangement fordriving a piston in a reservoir comprising a displaceable piston. Thereservoir unit may comprise more than one reservoir and more than oneexpelling assembly. For example, a single expelling assembly may be usedto expel drug from more than one reservoir, either simultaneouslythereby mixing drugs or alternating, or each reservoir may be providedwith an expelling assembly which may be connected to a commontranscutaneous device or to individual transcutaneous devices, e.g. thetranscutaneous device unit may comprise more than one transcutaneousdevice adapted to be connected to a expelling assembly.

In order to provide an initially sterile flow path through the pump, theflow path may be arranged between the inlet and outlet such that theinlet and outlet seal the interior of the pump and thereby the flow pathin an initial sterile state. By this arrangement it will not benecessary to provide the reservoir unit as an entirely sterileunit—indeed, the drug will have to be provided in a sterile state.

In an exemplary embodiment, the reservoir unit is transformable from aninitial condition in which there is no fluid communication between thepump and the reservoir to a non-reversible operating condition in whichfluid communication is established between the inlet means of the pumpand the outlet means of the reservoir when the pump unit is secured to aneedle unit for the first time. By this arrangement it is avoided thatundesired matter is introduced into the reservoir during re-connectionbetween the pump and the reservoir.

To secure a clean connection between the pump and the reservoir, aseparate fluid connector may be arranged within the interior of the pumpin the initial condition. Such a fluid connector may comprise a pointedinlet end and an outlet, whereas the inlet of the pump and the outlet ofthe reservoir may be in the form of two needle-penetratable septa. Bythis arrangement the pointed end of the fluid connector, e.g. aconnection needle, can be moved through the two septa and thus betweenthe initial condition and an operating condition in which fluidcommunication is established between the interior of the reservoir andthe interior of the pump via the fluid connector, the outlet of thefluid connector being arranged in the flow path. Advantageously thefluid connector is moved between its two positions as the reservoir unitis connected to a transcutaneous device unit for the first time.Correspondingly, during such a first connection two fluid communicationswill be established (between the transcutaneous device of thetranscutaneous device and the pump, and between the pump and thereservoir), whereas during subsequent connections only a single newfluid communication will be established (between the transcutaneousdevice of the transcutaneous device unit and the pump).

In an exemplary embodiment the transcutaneous device comprises a firstportion having a pointed distal end, and a second portion in fluidcommunication with the first portion and having a second end.Advantageously the second end of the transcutaneous device is pointedand the outlet means of the pump comprises a needle-penetratable septumallowing a fluid communication to be established between the second endof the transcutaneous device and the interior of the pump, preferably asthe two units are connected to each other.

Correspondingly, in a further aspect the present invention provides apump having an inlet means adapted to be arranged in fluid communicationwith a fluid supply, and an outlet means, the pump comprising aninternal flow path arranged between the inlet and outlet means, theinlet and outlet means sealing the interior of the pump and thereby theflow path in an initial sterile condition, wherein a fluid connectionmeans is arranged within the interior of the pump in the initialcondition, the fluid connection means comprising an inlet end and anoutlet, whereby the fluid connection means is arranged to be movedbetween the initial condition and to an operating condition in which theinlet end projects from the pump inlet means, whereby a fluidcommunication can be established between the fluid supply and theinterior of the pump via the fluid connection means and with the outletof the fluid connection means being arranged in the flow path.

The transcutaneous device unit may be supplied with e.g. a needleprojecting from the mounting surface, however, to limit the risk ofaccidental needle injuries, the pointed end of the transcutaneous deviceis advantageously moveable between an initial position in which thepointed end is retracted relative to the mounting surface, and anextended position in which the pointed end projects relative to themounting surface. Depending on the intended method of mounting thedevice on the user, the transcutaneous device may be moved between thetwo positions as the two units are connected to each, as would beappropriate in case the transcutaneous device unit is mounted on theskin of the user before the reservoir unit is connected. However, incase the two units are intended to be connected to each other beforeassembled units are mounted on the skin of the user, the transcutaneousdevice unit advantageously comprises user-actuatable actuation means formoving the pointed end of the transcutaneous device between the initialand the extended position.

To prevent inadvertent actuation of the transcutaneous device before thetwo units are assembled, the transcutaneous device unit may comprisemeans for blocking the actuation means, the blocking means beingreleased when the transcutaneous device unit and the reservoir unit aresecured to each other, thereby allowing the actuation means to beactuated.

To further reduce the likelihood of transcutaneous device injuries, thepointed end of the transcutaneous device may be moveable between theextended position in which the pointed end projects relative to themounting surface, and a retracted position in which the pointed end isretracted relative to the mounting surface. Correspondingly, thecombined device may comprise user-actuatable retraction means for movingthe pointed end of the transcutaneous device between the extended andthe retracted position when the retraction means is actuated. To preventre-use of the transcutaneous device, the transcutaneous device may bepermanently locked in its retraced position.

To prevent user-errors the actuation means for introducing thetranscutaneous device may in an initial condition cover the retractionmeans, actuation of the actuation means uncovering the retraction means.For example, the actuation means may be in the form of gripping means(e.g. a strip) which is removed from the device, whereby removaltriggers transcutaneous device insertion and at the same time uncoversthe retraction for withdrawing the transcutaneous device.

As described above, the expelling assembly may be activated anddeactivated when the two units are assembled and disassembled, however,the actuation and retraction means may also be used to activaterespectively deactivate the expelling assembly. Just as for the initialconnection between the pump and the reservoir, the initial activation ofthe expelling assembly may result in electronic control means beingactivated resulting in start of pumping action, whereas subsequentdeactivation will only deactivate the actual pump action, the controlmeans still being active (e.g. counting the time since initialactivation of the control means).

In the above disclosure of the invention the two units have beendescribed primarily as “unitary” units, however, this is only anexemplary configuration and these two “main” units may in case it isdeemed desirable be subdivided into further units. For example, thereservoir unit may be provided with an exchangeable control unit, thisallowing different types of control units to be connected to thereservoir unit per se. e.g. a first type of control unit may provide asingle delivery profile, a second control unit may be programmable tothereby modify the delivery pattern, or a control third unit maycomprise means allowing the control unit to communicate with externalmeans. In the latter case the control unit may be controlled using acordless remote control. Correspondingly, the reservoir may beexchangeable allowing different sizes of reservoirs or different typesof drugs to be used.

In a further aspect of the invention, a transcutaneous device unit isprovided as described above and being adapted to be used in combinationwith a reservoir unit as disclosed above. Correspondingly, the inventionalso provides a reservoir unit as disclosed above, the reservoir unitbeing adapted to be used in combination with a transcutaneous deviceunit as disclosed above. In an exemplary embodiment such atranscutaneous device unit may be provided with a hollow needlecomprising a pointed distal end with an outlet opening-and being adaptedto penetrate the skin of a subject, and a pointed proximal end with aninlet opening forming a fluid inlet means, the fluid inlet means beingadapted to be arranged in fluid communication with a fluid supply. Bythis arrangement the needle provides a hydraulically stiff fluidcommunication between the needle inlet and outlet openings (e.g. madefrom metal), this allowing early occlusion detection by monitoring apressure build-up upstream of the needle.

In a yet further aspect, a system is provided comprising a first needleunit and a first reservoir unit as disclosed above in combination with aleast one further needle unit or reservoir unit as disclosed above, thefurther unit(s) having different capabilities than the first units. Thedifferent capabilities may relate to any constructional feature of theunits, e.g. the type of needle, the type of user-actuatable means, thetype of delivery/pump means, or the type of reservoir/drug.

More specifically, in an exemplary embodiment a system is providedcomprising a transcutaneous device unit as disclosed above, and aplurality of reservoir units, each comprising a reservoir containing afluid drug, and an expelling assembly for expelling fluid drug from thereservoir. The transcutaneous device unit and the reservoir unitscomprise mating coupling means allowing a reservoir unit to be securedto the transcutaneous device unit to provide fluid communication betweenthe reservoir and the transcutaneous device, wherein each combination ofa transcutaneous device unit and a reservoir unit provides an assemblyhaving different capabilities. The different capabilities may berealized providing e.g. reservoir units with different amounts of thesame drugs, reservoir units with different drugs or variants of a givendrug, reservoir units adapted to expel drug at different preset rates,reservoir units adapted to expel at fixed respectively selectable rates.One of the reservoir units may be provided with a processor controllingthe expelling assembly and a receiver operatable coupled to thecontroller for receiving flow instructions from a separate controldevice and delivering the flow instructions to the processor. Thereceiver may be a wireless receiver. The reservoir units may further beprovided with different input means (e.g. for wireless or non-wirelessconnection, or manual input), or different output means (e.g. forwireless or non-wireless connection, different display means, ordifferent alarm means).

In a further exemplary embodiment, a system is provided comprising aplurality of transcutaneous device units as described above, and areservoir unit comprising a reservoir containing a fluid drug, and anexpelling assembly for expelling fluid drug from the reservoir. Thetranscutaneous device units and the reservoir unit comprise matingcoupling means allowing a transcutaneous device unit to be secured tothe reservoir unit to provide fluid communication between the reservoirand the transcutaneous device, wherein each combination of atranscutaneous device unit and a reservoir unit provides an assemblyhaving different capabilities. The different capabilities may berealized by providing the transcutaneous device units with differenttranscutaneous devices such as a hollow subcutaneous needle, a cannulaand insertion needle assembly, and a micro needle array, by providingdifferent adhesives, by providing different insertion or retractionmeans, or by providing different coupling means.

In a yet further exemplary embodiment, a system is provided comprising atranscutaneous device unit comprising a transcutaneous device and amounting surface adapted for application to the skin of a subject, areservoir unit comprising a reservoir containing a fluid drug, and atleast a portion of an expelling assembly for expelling fluid drug fromthe reservoir, and a plurality of control units, each comprising acontroller for controlling an expelling assembly, each having differentcapabilities. The transcutaneous device unit and the reservoir unitcomprise mating coupling means allowing the reservoir unit to be securedto the transcutaneous device unit to provide fluid communication betweenthe reservoir and the transcutaneous device, and the controller unitsand the reservoir unit comprise mating coupling means allowing acontroller unit to be secured to the reservoir unit to control theexpelling assembly, whereby each combination of a transcutaneous deviceunit, a reservoir unit and a control unit provides an assembly havingdifferent capabilities. The control units may have different controlfunctions as described above in respect of a system comprising aplurality of reservoir units. In an alternative configuration thereservoir unit and the transcutaneous device unit may be provided as aunitary structure adapted to cooperate with the control unit.

The present invention also provides a method comprising the steps ofproviding a transcutaneous device unit comprising a transcutaneousdevice and a mounting surface, providing a reservoir unit comprising areservoir adapted to contain a fluid drug, and an expelling assembly forexpelling fluid drug from the reservoir, the method comprising thefurther step of assembling the transcutaneous device unit and thereservoir unit to provide a fluid communication between the reservoirand the transcutaneous device. The fluid communication between thetranscutaneous device and the reservoir may be established when the twounits are assembled or it may be established when the assembled deviceis further actuated, both options being covered by the above definition.The method may comprise the further steps of mounting the mountingsurface to a skin surface of a subject, and, after mounting the mountingsurface to the skin surface of the subject, actuating the transcutaneousdevice to establish a fluid communication between the reservoir and thesubject.

A further method provides a drug delivery device dispensing a drug at apreset rate, the method comprising the steps of providing a systemcomprising a transcutaneous device unit comprising a transcutaneousdevice and a mounting surface adapted for application to the skin of asubject, the system further comprising a plurality of reservoir units,each comprising a reservoir containing a fluid drug, and an expellingassembly for expelling fluid drug from the reservoir at a preset rate,selecting a reservoir unit having a desired preset rate, and assemblingthe transcutaneous device unit and the selected reservoir unit toprovide a fluid communication between the reservoir and thetranscutaneous device.

In the above disclosure the present invention has been described withreference to a drug delivery device, however, the concept of theinvention can be regarded as a modular system providing a number ofadvantages. Thus, the transcutaneous device unit may also be in the formof a needle sensor and the “reservoir unit” may correspondingly be inthe form of a device adapted to transmit and/or process data acquiredvia the sensor.

As used herein, the term “drug” is meant to encompass anydrug-containing flowable medicine capable of being passed through adelivery means such as a hollow needle in a controlled manner, such as aliquid, solution, gel or fine suspension. Representative drugs includepharmaceuticals such as peptides, proteins, and hormones, biologicallyderived or active agents, hormonal and gene based agents, nutritionalformulas and other substances in both solid (dispensed) or liquid form.In the description of the exemplary embodiments reference will be madeto the use of insulin. Correspondingly, the term “subcutaneous” infusionis meant to encompass any method of transcutaneous delivery to asubject. Further, the term needle (when not otherwise specified) definesa piercing member adapted to penetrate the skin of a subject.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention will be further described with referencesto the drawings, wherein

FIGS. 1-11 shows in perspective views the sequences of use for a firstembodiment of a drug delivery device,

FIG. 12 shows a further embodiment of a reservoir unit,

FIG. 13 shows in a non-assembled state a needle unit and a reservoirunit for a further embodiment of a drug delivery device,

FIG. 14 shows an exploded view of the needle unit of FIG. 13,

FIG. 15 shows a perspective view of the needle unit of FIG. 13 in afirst state,

FIG. 16 shows a perspective view of the needle carrier of FIG. 14,

FIG. 17 shows a perspective view of the needle unit of FIG. 13 in asecond state,

FIG. 18 shows a side view of the needle unit of FIG. 13,

FIG. 19 shows a further perspective view of the needle unit of FIG. 13,

FIG. 20 shows perspective view of the interior of the reservoir unit ofFIG. 13,

FIG. 21 shows an exploded view of a further reservoir unit,

FIG. 22A shows a schematic overview of a pump connected to a reservoir,

FIG. 22B shows an exploded view of a pump assembly,

FIG. 22C shows a cross-sectional view of the pump assembly of FIG. 22C,

FIGS. 22D and 22E show partial cross-sectional views of the pumpassembly of FIG. 22C,

FIGS. 23A and 23B show in a schematic representation a transcutaneousdevice in the form of a cannula and insertion needle combination,

FIG. 24 shows a perspective view of a further drug delivery device,

FIGS. 25A-25D show different expelling means suitable for use with theinvention,

FIG. 26 shows a medical device with a modular reservoir unit, and

FIG. 27 shows a modular system for a medical device.

In the figures like structures are mainly identified by like referencenumerals.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

When in the following terms such as “upper” and “lower”, “right” and“left”, “horizontal” and “vertical” or similar relative expressions areused, these only refer to the appended figures and not to an actualsituation of use. The shown figures are schematic representations forwhich reason the configuration of the different structures as well asthere relative dimensions are intended to serve illustrative purposesonly.

Firstly, with reference to FIGS. 1-12 an embodiment of a drug deliverydevice will be described focusing primarily on the directlyuser-oriented features. The transcutaneous device unit 2 comprises atranscutaneous device in the form of a hollow infusion needle and willthus in the following be termed a needle unit, however, the needle maybe replaced with any desirable transcutaneous device suitable fordelivery of a fluid drug.

More specifically, FIG. 1 shows a perspective view of medical device inthe form of a modular skin-mountable drug delivery device 1 comprising apatch-like needle unit 2 and a reservoir unit 5. When supplied to theuser each of the units are preferably enclosed in its own sealed package(not shown).

The needle unit comprises a base portion 10 with a lower mountingsurface adapted for application to the skin of a user, and a housingportion 20 in which a hollow infusion needle (not shown) is arranged.The needle comprises a first needle portion having a pointed distal endadapted to penetrate the skin of a user, and a second pointed endadapted to be arranged in fluid communication with the reservoir unit.In the shown embodiment the pointed end of the needle is moveablebetween an initial position in which the pointed end is retractedrelative to the mounting surface, and an extended position in which thepointed end projects relative to the mounting surface. Further, theneedle is moveable between the extended position in which the pointedend projects relative to the mounting surface, and a retracted positionin which the pointed end is retracted relative to the mounting surface.The needle unit further comprises user-gripable actuation means in theform of a first strip-member 21 for moving the pointed end of the needlebetween the initial and the second position when the actuation means isactuated, and user-gripable retraction in the form of a secondstrip-member 22 means for moving the pointed end of the needle betweenthe extended and the retracted position when the retraction means isactuated. As can be seen, the second strip is initially covered by thefirst strip. The housing further comprises user-actuatable male couplingmeans 40 in the form of a pair of resiliently arranged hook membersadapted to cooperate with corresponding female coupling means on thereservoir unit, this allowing the reservoir unit to be releasablesecured to the needle unit in the situation of use. In the shownembodiment the base portion comprises a relatively rigid upper portion11 attached to a more flexible adhesive sheet member 12 having a loweradhesive surface providing the mounting surface per se, the adhesivesurface being supplied with a peelable protective sheet. The baseportion also comprises a ridge member 13 adapted to engage acorresponding groove on the reservoir unit.

The reservoir unit 5 comprises a pre-filled reservoir containing aliquid drug formulation (e.g. insulin) and expelling means in the formof an electronically controlled pump for expelling the drug from thereservoir through the needle in a situation of use. The reservoir unithas a generally flat lower surface adapted to be mounted onto the uppersurface of the base portion, and comprises a protruding portion 50adapted to be received in a corresponding cavity of the housing portion20 as well as female coupling means 51 adapted to engage thecorresponding hook members 31 on the needle unit. The protruding portionprovides the interface between the two units and comprises a pump outletand contact means (not shown) allowing the pump to be started as the twounits are assembled. The lower surface also comprises a window (not tobe seen) allowing the user to visually control the contents of thereservoir.

First step in the mounting procedure is to assemble the two units bysimply sliding the reservoir unit into engagement with the needle unit(FIG. 2). When the hook members properly engage the reservoir unit a“click” sound is heard (FIG. 3) signalling to the user that the twounits have been properly assembled. If desired, a visual or audiblesignal may also be generated. Thereafter the user removes the peelablesheet 14 to uncover the adhesive surface (FIG. 4) where after the devicecan be attached to a skin surface of the user, typically the abdomen(FIG. 5). Infusion of drug is started by gripping and pulling away theactuation strip 21 as indicated by the arrow whereby the needle isinserted followed by automatic start of the infusion (FIG. 6). Theneedle insertion mechanism may be supplied in a pre-stressed state andsubsequently released by the actuation means or the needle insertion maybe “energized” by the user. A “beep” signal confirms that the device isoperating and drug is infused. The reservoir unit is preferably providedwith signal means and detection means providing the user with an audiblealarm signal in case of e.g. occlusion, pump failure or end of content.

After the device has been left in place for the recommended period oftime for use of the needle unit (e.g. 48 hours)—or in case the reservoirruns empty or for other reasons—it is removed from the skin by gripping(FIG. 7) and pulling (FIG. 8) the retraction strip 22 as indicated bythe arrows which leads to retraction of the needle followed by automaticstop of drug infusion where after the strip which is attached to theadhesive patch is used to remove the device from the skin surface (FIG.9).

When the device has been removed the two units are disengaged bysimultaneously depressing the two hook members 31 as indicated by thearrows (FIG. 10) allowing the reservoir unit 5 to be pulled out ofengagement with the needle unit 2 as indicated by the arrow (FIG. 11)which can then be discarded. Thereafter the reservoir unit can be usedagain with fresh needle units until it has been emptied.

The reservoir unit may be supplied with a fixed basal infusion rate orit may be supplied as an adjustable unit (FIG. 12) with adjustment means55 allowing the infusion rate to be set by a physician and/or theuser/patient. The reservoir unit may also be provided with meansallowing the control means to be programmed or set electronically (notshown).

The device described with reference to FIGS. 1-11 may also be used inalternative ways. For example, the needle unit may be mounted to theskin after which the reservoir is attached. Depending on theconfiguration of the needle unit, it may be possible or prevented thatthe needle is introduced before the reservoir unit is attached.

FIG. 13 shows a further embodiment of medical device 500 substantiallycorresponding to the embodiment of FIG. 1, the device comprising apatch-like needle unit 502 and a thereto attachable reservoir unit 505.

FIG. 14 shows an exploded perspective view of the needle unit comprisingan upper housing portion 510, a needle carrier 520 and a thereto mountedinfusion needle 530, an actuation member 540, a release member 550, alower housing portion 560 and a sheet member 570. The actuation membercomprises a user gripable portion 541 and a needle actuation portion542, and the release member comprises a user gripable portion 551 and aneedle retraction portion 552. In the assembled state as shown in FIG.15, the upper and lower housing portions form a housing 503 in which theneedle and the needle carrier is mounted, the actuation and releasemembers being operatable connected to the needle carrier with the usergripable portions arranged outside the housing. In contrast to the FIG.1 embodiment does the needle unit not comprise a base plate portion butinstead two ridge members 561 extending from the housing, the ridgemembers and the lower surface of the housing being mounted on theflexible sheet member which is provided with a lower adhesive layer 571on its lower surface allowing the needle unit to be attached to a skinsite of a subject. The sheet member further comprises an opening 572arranged in register with a lower protrusion 565 provided around theexit aperture for the transcutaneous device, just as the sheet isprovided with a large number of small perforations to improvebreathability through the sheet. The housing 503 is provided with useractuatable coupling means 511 allowing a reservoir unit to be attachedto and released from the needle unit 505, the reservoir unit comprisingcorresponding mating coupling means 506 as well as a display 587. Thedisplay may indicate e.g. proper function of the unit, the amount ofdrug in the reservoir or different error conditions.

As seen is the user gripable portion 551 of the release member initiallycovered by a portion of the actuation member, this reducing theprobability that the user erroneously uses the release member instead ofthe actuation member. Further, the actuation and release members (orportion thereof) may be colour coded to further assist the user tocorrectly use the device. For example, the actuation member may be greento indicate “start” whereas the release member may be red to indicate“stop”.

FIG. 16 shows in perspective the needle carrier 520 with the needle 530and the needle actuation portion 542 of the actuation member 540. Theneedle actuation portion comprises two legs 543 allowing it to sliderelative to the housing, the legs being arranged through respectiveopenings 563 in the housing. The needle carrier is adapted to beconnected to a hinge member 562 of the lower housing portion to therebyallow the needle carrier and thereby the needle to pivot correspondingto a pivoting axis defined by a hinge. In the shown embodiment is theneedle carrier in the form a bent sheet metal member, the carriercomprising an upper arm 521 and a lower arm 522 connected to each otherby a hinge portion 523 allowing the lower arm to pivot relative to theupper arm and corresponding to the pivoting axis. The lower arm forms atray in which the hollow infusion needle 530 is mounted (e.g. by weldingor adhesive), the needle having a distal pointed portion 531 adapted topenetrate the skin of the subject, the distal portion extendinggenerally perpendicular to the mounting surface of the needle unit, anda proximal portion 532 arranged substantially corresponding to thepivoting axis and adapted to engage a fluid supply. Thus, when a portionof the upper arm is mounted in the housing, the lower arm can pivotbetween a first retracted position in which the distal portion of theneedle is retracted within the housing, and a second extended positionin which the distal portion projects relative to the mounting surface.In the shown embodiment the needle carrier provides the drive means formoving the lower arm between the two positions.

This may as in the present embodiment be provided by the elasticproperties of the sheet material per se corresponding to the hingeportion, or alternatively an additional spring may be provided betweenthe two arms to thereby urge them apart. To lock the lower part in anenergized, releasable first position, the upper arm is provided with aflexible release arm 526 comprising a catch 527 supporting and arrestingthe lower arm in its first downwardly biased position, as well as arelease portion 528 engaging a ramp surface 544 of the needle actuationportion 542, the catch further comprising an inclined edge portion 529adapted to engage the lower arm when the latter is moved from itsextended to its retracted position as will be described in greaterdetail below.

To actuate the needle the user grips the flexible strip forming the usergripable portion 541 (which preferably comprises adhesive portions tohold it in its shown folded initial position) and pulls the needleactuation portion 542 out of the housing, the actuation member 540thereby fully disengaging the housing. More specifically, when the rampsurface 544 is moved it forces the latch 527 away from the lower arm tothereby release it, after which the release portion 528 disengages theramp allowing the two legs to be pulled out of the housing. As seen inFIG. 17, when the actuation member is removed the user gripable portion551 of the release member is exposed. As for the actuation member, theuser gripable portion of the release member preferably comprisesadhesive portions to hold it in its shown folded initial position.

In the shown embodiment the release member is in the form of a stripformed from a flexible material and having an inner and an outer end,the strip being threaded through an opening 512 in the housing, thestrip thereby forming the user gripable portion 551 and the needleretraction portion 552, the inner end of the strip being attached to thehousing and the outer end of the strip being attached to a peripheralportion of the sheet member 570 or, alternatively, a peripheral portionof the housing. In the projection shown in FIG. 18 the release member isshown in its initial position, the retraction portion forming a loop 555arranged below the lower arm of the needle carrier, this positionallowing the lower arm to be moved to its actuated position and therebythe needle to its extended position.

When the user decides to remove the needle unit from the skin, the usergrips the user gripable portion 551, lifts it away from the housing andpulls it upwardly whereby the loop shortens thereby forcing the lowerarm upwardly, this position corresponding to an intermediate releasestate. By this action the lower arm engages the inclined edge portion529 of the catch 527 thereby forcing it outwardly until it snaps backunder the lower arm corresponding to the position shown in FIG. 16. Asthe actuation member 540 has been removed from the needle unit, theneedle carrier is irreversibly locked in its retracted position. Whenthe user further pulls in the release member, the peripheral portion ofthe sheet member to which the release member is attached will be liftedoff the skin, whereby the needle unit with its attached reservoir unitcan be removed from the skin, this as shown and described with referenceto FIGS. 7-9.

Advantageously, the actuation and release members may be formed andarranged to communicate with the reservoir unit (not shown). Forexample, one of the legs of the actuation member may in its initialposition protrude through the housing to thereby engage a correspondingcontact on the reservoir unit, this indicating to the reservoir unitthat the needle unit has been attached, whereas removal of the actuationmember will indicate that the needle has been inserted and thus thatdrug infusion can be started. Correspondingly, actuation of the releasemember can be used to stop the pump.

In FIG. 19 the side of the needle unit 502 which connects to thereservoir unit is shown. In addition to the two ridge members 561 andthe user actuatable coupling means 511 the needle unit comprises furtherstructures which connects to and/or engages the reservoir unit toprovide a functional interface with the reservoir unit. Morespecifically, the needle unit comprises a fluid inlet provided by thepointed proximal portion 532 of the needle projecting from the needleunit and adapted to engage a fluid outlet of the reservoir unit, anactuator 515 projecting from the needle unit and adapted to engage andactuate a fluid connector in the reservoir unit (see below), and firstand second contact actuators 548, 558 adapted to engage correspondingcontacts on the reservoir unit. The first contact actuator is providedby the distal end of one of the legs 543 of the needle actuatorprojecting through an opening in the housing, and the second contactactuator is provided by a hinged portion of the housing connected to theneedle retraction portion 552 of the release member 550. When the needleunit is first connected to the reservoir unit both contact actuatorswill protrude from the housing and engage the corresponding contacts onthe reservoir unit thereby indicating that that a needle unit has beenconnected. When the needle is actuated the first contact actuator willbe withdrawn and thereby disengage the corresponding contact on thereservoir unit to start pump actuation. When the needle is retracted thesecond contact actuator will pivot and disengage the correspondingcontact on the reservoir unit to stop pump actuation.

FIG. 20 shows the reservoir unit with an upper portion of the housingremoved. The reservoir unit comprises a reservoir 760 and an expellingassembly comprising a pump assembly 300 and control and actuation means580, 581 therefore. The pump assembly comprises an outlet 322 forconnection to a transcutaneous access device (e.g. the needle 530) andan opening 323 allowing an internal fluid connector to be actuated, seebelow. The reservoir 560 is in the form of prefilled, flexible andcollapsible pouch comprising a needle-penetratable septum adapted to bearranged in fluid communication with the pump assembly, see below. Theshown pump assembly is a mechanically actuated membrane pump, however,the reservoir and expelling means may be of any suitable configuration,e.g. as disclosed with reference to FIGS. 25A-25D.

The control and actuation means comprises a pump actuating member in theform of a coil actuator 581 arranged to actuate a piston of the membranepump, a PCB or flex-print to which are connected a microprocessor 583for controlling, among other, the pump actuation, contacts 588, 589cooperating with the contact actuators on the needle unit, signalgenerating means 585 for generating an audible and/or tactile signal, adisplay (not shown) and an energy source 586. The contacts arepreferably protected by membranes which may be formed by flexibleportions of the housing.

In FIG. 21 an exploded view of the reservoir unit 505 of FIG. 13 isshown, the unit comprising an upper housing member 507, a lower housingmember 508 with a transparent area 509 and grooves 504 to receive theridge members 561 extending from the needle unit, a flexible reservoir760 with a rounded edge portion 762 on which a septum member 761 ismounted, a pump assembly 300 with actuator and a circuit board (notshown) arranged above the reservoir and comprising electronic componentsfor controlling actuation of the pump. The upper and lower housingmembers comprise reservoir mounting means in the form of opposed upperand lower ridge portions 780 (the lower not seen) adapted to engage andmount the reservoir in the housing. Each ridge portion comprises acentral cut-out portion 781 adapted to engage the septum member on itsopposed surfaces when the housing members are assemble thereby lockingthe reservoir in place within the housing. The degree of locking will bedetermined by the pressure exerted on the septum member, the elasticproperties of the septum member and the friction between the ridge andthe septum member. On each side of the cut-out portion the ridgeportions comprise a straight portion 782 which may aid in mounting thereservoir in the housing. The straight portions may engage the initiallyprefilled reservoir to help lock it in place, however, as the reservoiris emptied and flattens this grip may lessen. In contrast, theengagement with the septum is adapted to lessen. In contrast, theengagement with the septum is adapted to properly hold the reservoir inplace as the reservoir is emptied. The straight portions may also beadapted to pinch and fully flatten the reservoir thus serving as anadditional mounting means. Additional mounting means (not shown) mayengage and grip the reservoir at other locations, e.g. along the weldededges 765.

With reference to FIG. 22A a schematic overview of a pump connected to areservoir is shown, the pump comprising the following general features:a fluid connection 391 to reservoir a reservoir 390, a safety valve 392,inlet and outlet valves 393, 394, a pump chamber 395 with an associatedpiston 396, and an outlet 397. The arrows indicate the flow directionbetween the individual components. When the piston is moved downwards(in the drawing) a relative negative pressure will build up inside thepump chamber which will cause the inlet valve to open and subsequentlyfluid will be drawn form the reservoir through the open primary side ofthe safety valve. When the piston is moved upwards (in the drawing) arelative overpressure will build up in the pump chamber which will causethe inlet valve to close and the outlet valve and the safety valve toopen whereby fluid will flow from the pump chamber through the outletvalve and the secondary side of the safety valve to the outlet. Asappears, in normal operation the safety valve allows fluid passageduring both intake and expelling of fluid and is thus “passive” duringnormal operation. However, in case the reservoir is pressurized (as mayhappen for a flexible reservoir) the elevated pressure in the reservoirwill be transmitted to both the primary side of the safety valve and,via the pump chamber, the secondary side of the safety valve in whichcase the pressure on the primary side of the safety valve will preventthe secondary side to open.

In FIG. 22B an exploded view of a pump assembly 300 utilizing the pumpprinciple depicted in FIG. 22A is shown, the pump assembly (in thefollowing also referred to as a pump) being suitable for use with thereservoir units of FIGS. 1-13. The pump is a membrane pump comprising apiston-actuated pump membrane with flow-controlled inlet- andoutlet-valves. The pump has a general layered construction comprisingfirst, second and third members 301, 302, 303 between which areinterposed first and second membrane layers 311, 312, whereby a pumpchamber 341 is formed by the first and second members in combinationwith the first membrane layer, a safety valve 345 is formed by the firstand third members in combination with the first membrane layer, andinlet and outlet valves 342, 343 are formed by the second and thirdmembers in combination with the second membrane layer (see FIG. 22C).The layers are held in a stacked arrangement by an outer clamp 310. Thepump further comprises an inlet 321 and an outlet 322 as well as aconnection opening 323 which are all three covered by respectivemembranes 331, 332, 333 sealing the interior of the pump in an initialsterile state. The membranes are penetratable or breakable (e.g. madefrom paper) by a needle or other member introduced through a given seal.The outlet further comprises a self-sealing, needle-penetratable septa334 (e.g. of a rubber-like material) allowing the pump to be connectedto an outlet needle. As shown in FIG. 22C a fluid path (indicated by thedark line) is formed between the inlet 321 (see below) and the inletvalve 342 via the primary side of the safety valve 345, between theinlet valve, pump chamber 345 and the outlet valve 343, and between theoutlet valve and the outlet 322 via the secondary side of the safetyvalve, the fluid paths being formed in or between the different layers.The pump also comprises a piston 340 for actuating the pump membrane,the piston being driven by external driving means (not shown).

The pump further comprises a fluid connector in the form of hollowconnection needle 350 slidably positioned in a needle chamber 360arranged behind the connection opening, see FIG. 22D. The needle chamberis formed through the layers of the pump and comprises an internalsealing septum 315 through which the needle is slidably arranged, theseptum being formed by the first membrane layer. The needle comprises apointed distal end 351, a proximal end on which is arranged a needlepiston 352 and a proximal side opening 353 in flow communication withthe distal end, the needle and the piston being slidably arrangedrelative to the internal septum and the chamber. As can be appreciatedform FIG. 22D the needle piston in its initial position is bypassed byone or more radially placed keyways 359. These are provided in order toallow steam sterilisation and to vent the air otherwise trapped when thefluid connector is moved forward in the needle chamber.

The above-described pump assembly may be provided in a drug deliverydevice of the type shown in FIGS. 1-20. In a situation of use where thereservoir unit is attached to a needle unit the proximal end 532 of theinfusion needle is introduced through the outlet seal and septum 334 ofthe pump, and the actuator 515 (see FIG. 19) is introduced through theconnection membrane 333. By this action the connection needle is pushedfrom its initial position as shown in FIG. 22D to a actuated position asshown in FIG. 22E in which the distal end is moved through the inletmembrane 331 and further through the needle-penetratable septum of anearby located reservoir, this establishing a flow path between thereservoir and the inlet valve via the proximal opening 353 in theneedle. In this position a seal is formed between the needle piston andthe needle chamber.

As appears, when the two units are disconnected, the proximal end 532 ofthe infusion needle is withdrawn from the pump outlet whereas theconnection needle permanently provides fluid communication between thepump and the reservoir.

In the above described embodiments, the transcutaneous device has beenin the form of a unitary needle device (e.g. an infusion needle as shownor a needle sensor (not shown)), however, the transcutaneous device mayalso be in the form of a cannula or a sensor in combination with aninsertion needle which is withdrawn after insertion thereof. Forexample, the first needle portion may be in the form of a (relativelysoft) infusion cannula (e.g. a Teflon® cannula) and a there througharranged removable insertion needle. This type of cannula needlearrangement is well known from so-called infusion sets, such infusionsets typically being used to provide an infusion site in combinationwith (durable) infusion pumps.

Thus, FIGS. 23A and 23B show in a schematic representation how a cannulaand insertion needle combination can be arranged within a housing 601 ofin a given medical device 600 (partly shown), e.g. an infusion device oran infusion set. More specifically, the medical device comprises atranscutaneous assembly 650 comprising a combination of a relativelysoft cannula 651 (which e.g. may be of the soft “Teflon®” type) carriedby a lower member 653 and a pointed insertion needle 661 (e.g. made frommedical grade stainless steel) slidably arranged within the cannula andcarried by an upper member 663, both members being mounted to allowaxial displacement of the cannula respectively the insertion needle. Thecannula comprises a proximal inlet (not shown) allowing it to be or tobe arranged in fluid communication with a fluid source. The medicaldevice further comprises a base plate 620 with an opening 621 for thecannula as well as a release member 622. The lower member comprises anelastomeric seal 652 through which the insertion needle is arranged. Thecannula and the insertion needle may be straight or curved dependentupon how the two members are mounted in the device, e.g. arcuatecorresponding to a pivoting axis or straight corresponding to linearmovement as illustrated. The upper member comprises a coupling member667 locking the members together in an initial position with distal endof the insertion needle extending from the distal opening of the cannulaas shown in FIG. 23A, and the base plate comprises coupling member 657for locking the lower member in an extended position with distal end ofthe cannula extending through the opening in the base plate (see FIG.23B). Between the housing of the device and the upper member a firstspring 668 is arranged biasing the upper member upwards.Correspondingly, the device also comprises a second spring 658 biasingthe lower member upwardly. The medical device further comprises agripping tab 676 and a pulling member 677 corresponding to theembodiment shown in FIG. 1.

In a situation of use the assembly is moved downwardly, either manuallyor by a releasable insertion aid, e.g. a spring loaded member actingthrough an opening in the housing (not shown) whereby the cannula withthe projecting insertion needle is inserted through the skin of asubject. In this position the lower member engages the coupling member657 to thereby lock the cannula in its extended position, just as thecoupling member 667 is released by the release member 622 therebyallowing the upper member to return to its initial position by means ofthe first spring.

When the user intends to remove the delivery device from the skinsurface, the user grips the gripping portion of the tab and pulls it ina first direction substantially in parallel with the skin surface, bywhich action the flexible strip 677 releases the coupling member 657from the lower member whereby the lower member and thereby the cannulais retracted by means of the second spring. When the cannula has beenwithdrawn from the skin, the user uses the now unfolded tab to pull offthe entire delivery device from the skin surface, for example by pullingthe tab in a direction away from the skin surface.

In FIG. 24 an embodiment of a device adapted for the latter mountingprocedure described with reference to FIGS. 1-12 is shown (i.e. mountingthe needle unit first).

More specifically, FIG. 24 shows a perspective view of medical device inthe form of a drug delivery device 100 comprising a needle housing 110,a base member 130 with a lower mounting surface 133 adapted forapplication to the skin of the subject, and a separate pump unit 150. Inthe shown embodiment the base member comprises a relatively rigid upperportion 131 attached to a more flexible adhesive patch member 132 havinga lower adhesive surface providing the mounting surface per se. Theneedle housing may be formed integrally with the base member or attachedthereto as a separate unit, the two elements in combination forming aplatform unit. In the shown embodiment the needle unit comprises ahousing 111 within which a hollow needle 112 is pivotally arranged.

The housing comprises first and second openings (or windows) covered byfirst and second cover means. In the shown embodiment the first covermeans is in the form of a needle penetratable rubber membrane 121 andthe second cover membrane is in the form of a breakable paper sheetallowing components to be introduced into the interior of the housing.The paper sheet is penetratable to sterilizing gases, the paper sheet,the rubber membrane and the housing in combination providing a sterilitybarrier for the encapsulated needle portion.

The needle comprises a first needle portion 113 having a first pointedend adapted to penetrate the skin of the subject, the first needleportion extending generally perpendicular to the mounting surface, and asecond needle portion 114 in fluid communication with the first needleportion via an intermediate needle portion 115 and having a secondpointed end, the second needle portion being arranged substantially inparallel with the mounting surface. The needle is connected to thehousing by a mounting member 117 allowing the needle to pivotcorresponding to an axis defined by the second needle portion, wherebythe needle is moveable between an initial sterile position in which thefirst needle portion is retracted relative to the mounting surface, anda second position in which the pointed end of the first needle portionprojects through the rubber septum and relative to the mounting surface.The housing also comprises a biasing member 118 biasing the needletowards the initial position. Often, the “downstream” portion of aneedle (here: the first portion) is referred to as the distal portion,and the “upstream” portion of a needle (here: the second portion) isreferred to as the proximal portion.

The reservoir (or pump) unit 150 comprises a housing in which areservoir and expelling means are arranged. The reservoir is adapted tocontain a liquid drug (e.g. prefilled or adapted to be filled by a user)and comprises an outlet means in the form of a protruding needlepenetratable septum 155 adapted to be arranged in fluid communicationwith the second needle portion. The expelling means (not shown) isadapted for in a situation of use to expel a drug out of the reservoirand through the skin of the subject via the hollow needle. The pump unitfurther comprises a ramp member 156 arranged next to the reservoiroutlet. The reservoir and expelling means may be of any suitableconfiguration, e.g. as disclosed with reference to FIGS. 25A-25D.

The mounting platform comprises a receiving portion, the receivingportion and the pump unit comprising mating coupling means 160 allowingthe pump unit to be secured to the platform unit. The mating couplingmeans may be releasable allowing a durable or multi-use pump unit to beattached a number of times to a disposable platform unit.

In a situation of use, the platform unit is mounted on the skin of auser (e.g. by adhesive means arranged on the mounting surface) and thepump unit is attached and locked to the platform unit by sliding it intoengagement therewith substantially in parallel with the mountingsurface. During the latter operation the protruding septum and the rampmember is moved into engagement with the needle, thereby breaking thepaper barrier cover 122, during which operation fluid communication isestablished between the second needle portion and the reservoir, just asthe needle is pivoted from its initial to its second position, the firstpointed needle end thereby penetrating the rubber membrane and the skinof the user.

After the pump unit has been connected and the needle introducedsubcutaneously, the pump can be started. This may happen eitherautomatically as the two units are connected or by separateuser-actuatable starting means, e.g. a start button (not shown).

In an alternative embodiment (not shown), the second needle portion maybe fixedly (i.e. non-rotationally) attached to the mounting member 117,the intermediate needle portion 115 being elastically bend as it isforced downwardly by the ramp member 156. In such an arrangement thebiasing member 118 may be dispensed with.

In the above-described embodiments a delivery device has been describedcomprising a flexible reservoir in combination with an example of anexpelling means. However, the reservoir and the expelling means may beof any type which would be suitable for arrangement within askin-mountable drug delivery device. Further, as the needle of thepresent invention also may be in the form of a needle sensor, theinterior of the medical device may comprise sensor means adapted tocooperate with the needle sensor.

In FIGS. 25A-25E examples of expelling means suitable for use with thepresent invention are shown schematically, however, these are merelyexamples, just as the shown arrangement of the individual components notnecessarily are suitable for direct application in the above showndelivery devices. More specifically, FIG. 25A shows a pump arrangementcomprising a drug-containing cartridge 1010 forming a reservoir andhaving a distal closure member 1011 allowing a needle to be connected,and a piston 1015 slidingly arranged there within, a flexible toothedpiston rod 1020 (for example as disclosed in U.S. Pat. No. 6,302,869),an electric motor 1030 which via a worm-gear arrangement 1031 drives thepiston rod to expel drug from the cartridge, the motor being controlledby control means 1040 and the energy for the control means and the motorbeing provided by a battery 1050. The pump may be activated when theneedle is inserted (by means not shown) or by separate user-actuatablemeans (not shown) after the inserter has been detached form the deliverydevice.

FIG. 25B shows a pump arrangement comprising a drug-containing cartridge1110 having distal and proximal closure members 1111, 1112, and a piston1115 slidingly arranged there within, gas generating means 1120 in fluidcommunication with the interior of the cartridge via conduit 1121 fordriving the piston to expel drug from the cartridge, the gas generatingmeans being controlled by control means 1140 and the energy for thecontrol means and the gas generation being provided by a battery 1150.The pump may be activated as indicated above. A detailed disclosure ofsuch gas generating means for a drug delivery device can be found ine.g. U.S. Pat. No. 5,858,001.

FIG. 25C shows a pump arrangement comprising a drug-containing cartridge1210 having distal and proximal closure members 1211, 1212, and a pistonslidingly 1215 arranged there within, an osmotic engine 1220 in fluidcommunication with the interior of the cartridge via conduit 1221 fordriving the piston to expel drug from the cartridge. The osmotic enginecomprises a first rigid reservoir 1225 containing a salt-solution and asecond collapsible reservoir 1226 containing water, the two reservoirsbeing separated by a semi-permeable membrane 1227. When supplied to theuser, the fluid connection 1228 between the second reservoir and themembrane is closed by a user-severable membrane (e.g. a weak weld)which, when severed, will allow the osmotic process to start as water isdrawn from the second reservoir through the membrane and into the firstreservoir. The pump may be activated as indicated above. A detaileddisclosure of the osmotic drive principle can be found in e.g. U.S. Pat.No. 5,169,390.

FIG. 25D shows a pump arrangement comprising a drug-containing flexiblereservoir 1310 arranged within a rigid fluid-filled secondary reservoir1311 in fluid communication with a primary reservoir 1320 through aconduit 1330 comprising a flow restrictor 1331. The primary reservoir isin the form of a cartridge with a moveable piston 1321 and contains aviscous drive fluid. A spring 1340 is arranged to act on the piston todrive fluid from the first to the second reservoir thereby expellingdrug from the flexible reservoir when the latter is connected to aninfusion needle (not shown). The flow rate will be determined by thepressure generated by the spring in the drive fluid, the viscosity ofthe drive fluid and the flow resistance in the flow restrictor (i.e.bleeding hole principle). The pump may be activated by straining thespring or by releasing a pre-stressed spring, either when the needle isinserted (by means not shown) or by separate user-actuatable means (notshown) after the inserter has been detached from the delivery device. Anexample of this principle used for drug infusion is known from DE 25 52446. In an alternative configuration, the drug reservoir may bepressurized directly to expel the drug via a flow restrictor, e.g. asdisclosed in U.S. Pat. No. 6,074,369.

In FIG. 26 is shown a medical device 900 corresponding to the embodimentof FIGS. 1-11, however, the reservoir unit has a modular designcomprising a “durable” control unit 910 adapted to be mounted on areservoir unit 920 comprising a reservoir and an expelling assemblycontrollable by the control unit through contacts 921. Thetranscutaneous device unit 930 may be the same as in FIGS. 1-11. Thetranscutaneous device unit and the reservoir unit comprise matingcoupling means (931) allowing the reservoir unit to be secured to thetranscutaneous device unit to provide fluid communication between thereservoir and the transcutaneous device, and the controller unit and thereservoir unit comprise mating coupling means (917, 921) allowing thecontroller unit to be secured to the reservoir unit to control theexpelling assembly. The control unit may comprise one or more of thefollowing features: a vibrator, a RF transmitter, a RF receiver, adisplay, a bolus button 918 (as shown) or other user input means, aback-up battery, a memory. Further, the control unit may be adapted toprovide a fixed flow rate or it may be programmable (e.g. via a remotecontrol) to provide a given rate or a given profile. The differentcontrol units may also be used with different reservoir units (e.g.comprising different drugs or different amounts of drugs), or withdifferent needle units (e.g. comprising a needle or a soft cannula). Asstated above, the controller may be used as a durable device by theuser, however, (simpler) versions of the controller may comepre-attached to a reservoir unit and be used as a means to provide avarity of disposable devices.

FIG. 27 shows a modular system comprising a number of different types ofcontrol units in addition to a basic needle patch unit 930 and a basicreservoir unit 920. A remote controller 940 may be used in combinationwith some of the control units. The control unit may be in the form of aremotely controllable unit 911 which can only be controlled from aremote controller. A variant 912 thereof may add a bolus button allowingthe user to take a bolus of drug without having to use the remotecontroller. The control unit may be provided as a varity ofpreprogrammed control units 913, each providing a fixed flow rate asindicated on the unit. Such a unit is intended for use without a remotecontroller and may include a display 919 as shown. A programmablecontrol unit 914 may also be provided, this allowing e.g. a medicalpractitioner to program the control unit for an individual patient. Adummy 915 represents any of the disclosed control units in combinationwith a reservoir unit and a needle unit.

In the above description of the preferred embodiments, the differentstructures and means providing the described functionality for thedifferent components have been described to a degree to which theconcept of the present invention will be apparent to the skilled reader.The detailed construction and specification for the different componentsare considered the object of a normal design procedure performed by theskilled person along the lines set out in the present specification.

1. A medical device, comprising a transcutaneous device unit and a separate reservoir unit, the transcutaneous device unit comprising: a transcutaneous device, and a mounting surface comprising a skin adhering adhesive, wherein the reservoir unit comprises: a reservoir adapted to contain a fluid drug, and an expelling assembly adapted for cooperation with the reservoir to expel fluid drug out of the reservoir and through the skin of the subject via the transcutaneous device, wherein the transcutaneous device unit and the reservoir unit are secured to each other in a situation of use, wherein the expelling assembly is activated or allowed to be activated to deliver fluid from the reservoir when the transcutaneous device unit and the reservoir unit are secured to each other and de-activated to stop fluid flow from the reservoir when the units are released from each other, and wherein the activation occurs by engaging an actuator on the transcutaneous device unit and deactivation occurs by disengaging the actuator.
 2. A medical device as defined in claim 1, wherein fluid communication between the transcutaneous device and the reservoir is established when the transcutaneous device unit and the reservoir unit are secured to each other.
 3. A medical device as in claim 1, wherein the expelling assembly is activated or allowed to be activated when the transcutaneous device unit and the reservoir unit are secured to each other and de-activated when the units are released from each other.
 4. A medical device as defined in claim 1, wherein the expelling assembly comprises a pump having an inlet adapted to be arranged in fluid communication with the reservoir, and an outlet adapted to be arranged in fluid communication with the transcutaneous device, thereby allowing the transcutaneous device to be arranged in fluid communication with the interior of the reservoir.
 5. A medical device as defined in claim 4, wherein the pump comprises an internal flow path arranged between the inlet and the outlet, the inlet and the outlet sealing the interior of the pump and thereby the flow path in an initial sterile state.
 6. A medical device as defined in claim 5, wherein the reservoir unit is transformable from an initial condition in which there is no fluid communication between the pump and the reservoir to a non-reversible operating condition in which fluid communication is established between the inlet of the pump and the reservoir when the pump unit is secured to a transcutaneous device unit for the first time.
 7. A medical device as defined in claim 6, wherein a fluid connector is arranged within the interior of the pump in the initial condition, the fluid connector comprising an inlet and an outlet, wherein the fluid connector is arranged to be operated from the initial condition and to an operating condition in which fluid communication is established between the interior of the reservoir and the interior of the pump via the fluid connector and with the outlet of the fluid connector being arranged in the flow path of the pump.
 8. A medical device as defined in claim 7, wherein the fluid connector comprises a pointed inlet end, the reservoir comprising a penetratable portion allowing the pointed fluid connector inlet end to be inserted there through.
 9. A medical device of claim 1, wherein the transcutaneous device comprises a pointed end adapted to penetrate the skin of a subject, the pointed end being moveable between an initial position in which the pointed end is retracted relative to the mounting surface, and an extended position in which the pointed end projects relative to the mounting surface.
 10. A medical device as defined in claim 9, wherein the transcutaneous device unit comprises a further actuator for moving the pointed end of the transcutaneous device between the initial and the extended position when the actuator is actuated.
 11. A medical device as defined in claim 10, wherein the transcutaneous device unit comprises an assembly for blocking the actuator, the blocking assembly being released when the transcutaneous device unit and the reservoir unit are secured to each other, thereby allowing the actuator to be actuated.
 12. A medical device as defined in claim 10, wherein the expelling assembly is activated when the actuator is actuated.
 13. A medical device as defined in claim 12, wherein the pointed end of the transcutaneous device is moveable between the extended position in which the pointed end projects relative to the mounting surface, and a retracted position in which the pointed end is retracted relative to the mounting surface.
 14. A medical device as defined in claim 13, further comprising a retraction component for moving the pointed end of the transcutaneous device between the extended and the retracted position when the retraction components is actuated.
 15. A medical device as defined in claim 14, wherein the actuator in an initial condition covers the retraction means, actuation of the actuator uncovering the retraction component.
 16. A medical device as defined in claim 14, wherein the expelling assembly is deactivated when the retraction component is actuated.
 17. A medical device as defined in claim 1, wherein the transcutaneous device comprises a first portion having a/the pointed end, and a second portion in fluid communication with the first portion and having a second end.
 18. A medical device as defined in claim 17, wherein the second end comprises a pointed needle end, the outlet of the pump comprising a needle-penetratable septum allowing a fluid communication to be established between the second end of the transcutaneous device and the interior of the pump.
 19. A medical device as defined in claim 1, wherein the mounting surface comprises adhesive allowing the medical device to be attached to a skin surface of the subject.
 20. A medical device as defined in claim 19 when dependent upon claim 14, wherein operation of the retraction component from a first to an intermediate condition causes the transcutaneous device to be moved from the extended position to the retracted position, and operation of the retraction component from the intermediate to a second condition causes release of the device from the skin surface.
 21. A medical device as defined claim 1, comprising releasable coupling for securing the transcutaneous device unit and the reservoir unit to each other.
 22. A medical device as defined in claim 21, wherein the expelling assembly is deactivated when the two units are released from each other.
 23. A medical device as in claim 1, wherein the reservoir is prefilled with a liquid drug.
 24. A medical device as in claim 1, wherein the reservoir, in a situation of use, comprises a liquid drug but substantially no enclosed free gas. 